1. Field of the Invention
The present invention relates to a mask for vacuum deposition and an organic EL display panel manufactured by using the same.
2. Description of the Related Art
In recent years, in the pixels of a light emitting device such as an organic EL, as colorization goes forward, a minimum pitch between RGB has been made as fine as nearly 50 μm and additionally, a study of making the pitch finer has been also conducted.
On the other hand, the size of a mask for vacuum deposition used for manufacturing the organic EL is as large as about from 400 mm to 500 mm and there has been a tendency for the mask for vacuum deposition to become larger with the increasing size of a display panel using the organic EL. In this manner, there has been a tendency that the mask for vacuum deposition used for manufacturing the light emitting device such as organic EL is made larger in size and that a mask pitch between its mask patterns is made narrower.
If the mask pitch of the mask for vacuum deposition that is made larger in size is made narrower, as described above, then the rigidity of the mask for vacuum deposition itself is decreased and thus when the mask for vacuum deposition is fixed to a mask frame of its holding member, a deflection is produced.
In order to remove the deflection, it is necessary to apply a tension to the mask for vacuum deposition. For this reason, in the related art, in the state where a tension is applied to the mask for vacuum deposition to remove the deflection, the end portion of the mask for vacuum deposition is bonded to the mask frame with an adhesive or is fixed welded thereto by welding, or is clamped with screws.
However, the conventional method of fixing the mask for vacuum deposition to the mask frame presents a problem that since it is difficult to adjust the tension of the mask for vacuum deposition after it is fixed, it is impossible to correct the mask for vacuum deposition when it is deflected by some causes after it is fixed.
Further, the above-described method in the related art presents a problem that since it is difficult to dismount the mask for vacuum deposition from the mask frame, it is difficult to clean the mask for vacuum deposition and to change the mask for vacuum deposition when the mask pattern of the mask for vacuum deposition is changed. Still further, the method in the related art presents a problem that since it is difficult to dismount the mask for vacuum deposition, the mask frame can not be used again.